Signal shaping based lattice codes for MIMO systems

This paper proposes a shaping-based codebook construction method for max-min Euclidean distance based multiple-input multiple-output (MIMO) transmit codebook design. Different from existing max-min precoder designs, shaping-based codebook construction jointly designs the precoding matrix and the modulated signal. Hyperrectangle is found to be a near optimal shaping region and given the hyperrectangle shaping region, the number of available spatial dimensions used for codebook construction is predetermined through maximizing the approximated constellation figure of merit. Then, the codebook is derived by lattice precoding and hyperrectangle shaping. Numerical results illustrate that our method is strictly better than present precoder-based codebook designs under different MIMO channel conditions.